From cefa94bd27f696b975cc7c3dc97ba7ecc91ef0cc Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Mon, 3 Jun 2019 15:07:03 -0700
Subject: [PATCH 1/2] Fix data race and ordering consistency in apex modules

apexDepsMutator can be called on multiple apex modules in parallel,
and then two goroutines could call BuildForApex on the same module
in parallel, leading to a data race appending to apexVariations.
This also results in random ordering of the entries in
apexVariations.

Hold a mutex around appending to apexVariations, and sort it before
passing it to ctx.CreateVariations.

Fixes: 134425751
Test: m nothing
Change-Id: If5a3b53a778daacb3e26ac05cde872cf8eb980b3
---
 android/apex.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/android/apex.go b/android/apex.go
index bf11ba25f..17df76240 100644
--- a/android/apex.go
+++ b/android/apex.go
@@ -15,6 +15,7 @@
 package android
 
 import (
+	"sort"
 	"sync"
 
 	"github.com/google/blueprint"
@@ -86,7 +87,9 @@ type ApexModuleBase struct {
 	ApexProperties ApexProperties
 
 	canHaveApexVariants bool
-	apexVariations      []string
+
+	apexVariationsLock sync.Mutex // protects apexVariations during parallel apexDepsMutator
+	apexVariations     []string
 }
 
 func (m *ApexModuleBase) apexModuleBase() *ApexModuleBase {
@@ -94,6 +97,8 @@ func (m *ApexModuleBase) apexModuleBase() *ApexModuleBase {
 }
 
 func (m *ApexModuleBase) BuildForApex(apexName string) {
+	m.apexVariationsLock.Lock()
+	defer m.apexVariationsLock.Unlock()
 	if !InList(apexName, m.apexVariations) {
 		m.apexVariations = append(m.apexVariations, apexName)
 	}
@@ -122,6 +127,7 @@ func (m *ApexModuleBase) IsInstallableToApex() bool {
 
 func (m *ApexModuleBase) CreateApexVariations(mctx BottomUpMutatorContext) []blueprint.Module {
 	if len(m.apexVariations) > 0 {
+		sort.Strings(m.apexVariations)
 		variations := []string{""} // Original variation for platform
 		variations = append(variations, m.apexVariations...)
 

From 4c2c46f0a72e21ffe6be407028b857ba461144d7 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Mon, 3 Jun 2019 15:26:05 -0700
Subject: [PATCH 2/2] Fix nondeterminstic iteration of vndk modules map

Sort the list of libraries when iterating over the vndk modules
map to avoid a non-deterministic output file.

Test: m nothing && mv out/soong/build.ninja /tmp && m nothing && diff -u out/soong/build.ninja /tmp/build.ninja
Change-Id: I889736715dab491bb7e69f3499ab1a5e2c876171
---
 cc/vndk.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/cc/vndk.go b/cc/vndk.go
index 5f9c686b5..f9f376432 100644
--- a/cc/vndk.go
+++ b/cc/vndk.go
@@ -530,8 +530,15 @@ func (c *vndkSnapshotSingleton) GenerateBuildActions(ctx android.SingletonContex
 
 	var modulePathTxtBuilder strings.Builder
 
+	modulePaths := modulePaths(ctx.Config())
+	var libs []string
+	for lib := range modulePaths {
+		libs = append(libs, lib)
+	}
+	sort.Strings(libs)
+
 	first := true
-	for lib, dir := range modulePaths(ctx.Config()) {
+	for _, lib := range libs {
 		if first {
 			first = false
 		} else {
@@ -539,7 +546,7 @@ func (c *vndkSnapshotSingleton) GenerateBuildActions(ctx android.SingletonContex
 		}
 		modulePathTxtBuilder.WriteString(lib)
 		modulePathTxtBuilder.WriteString(".so ")
-		modulePathTxtBuilder.WriteString(dir)
+		modulePathTxtBuilder.WriteString(modulePaths[lib])
 	}
 
 	ctx.Build(pctx, android.BuildParams{